Electric motors are used in a variety of applications, including power tools. Such electric motors typically include a motor shaft, a motor armature, magnets, a fan baffle, a commutator assembly, brushes and electrical leads. The electrical leads selectively link brushes to a power source. The motor armature is fixed for rotation with the motor shaft and a series of copper conducting wires are wound in various patterns about peripheral slots. Ends of the wires are fused to the commutator. The commutator is fixed for rotation with the motor shaft and provides an electrical connection between the rotating armature and the stationary brushes.
The brush is often held in place by an electrically conductive brush box. The electrical current powering the motor flows through this electrically conductive brush box through the brushes and into the commutator. As a result, the temperature of the brush box (which is typically made of brass) can be raised to fairly high levels; particularly when high amperage applications are concerned like battery operated power tools. As such, the temperature of the brush box can be sufficient to potentially damage the field case housing. Thus, it is desirable to minimize any such risk of damage.